Components of an Ecosystem
You are already familiar with the parts of an ecosystem. You have learned about
climate and soils from past lectures. From this course and from general knowledge,
you have a basic understanding of the diversity of plants and animals, and how plants
and animals and microbes obtain water, nutrients, and food. We can clarify the parts of
an ecosystem by listing them under the headings "abiotic" and "biotic".
ABIOTIC COMPONENTS
Sunlight
Temperature
Precipitation
Water or moisture
Soil or water chemistry (e.g., P, NH4+)
etc.
All of these vary over
BIOTIC COMPONENTS
Primary producers
Herbivores
Carnivores
Omnivores
Detritivores
etc.
space/time
By and large, this set of environmental factors is important almost everywhere, in all
ecosystems.
http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/ecosystem/ecosyste
m.html
Abiotic Factors
Abiotic factors are essentially non-living components that affect the living organisms of the
freshwater community.
When an ecosystem is barren and unoccupied, new organisms colonising the environment
rely on favourable environmental conditions in the area to allow them to successfully live
and reproduce.
These environmental factors are abiotic factors. When a variety of species are present in
such an ecosystem, the consequent actions of these species can affect the lives of fellow
species in the area; these factors are deemed biotic factors.
The light from the sun is a major constituent of a freshwater ecosystem, providing light for
the primary producers, plants. There are many factors which can affect the intensity and
length of time that the ecosystem is exposed to sunlight;
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Aspect - The angle of incidence at which light strikes the surface of the water. During the
day when the sun is high in the sky, more light can be absorbed into the water due to the
directness of the light. At sunset, light strikes the water surface more acutely, and less
water is absorbed. The aspect of the sun during times of the day will vary depending on
the time of the year.
Cloud Cover - The cloud cover of an area will inevitably affect intensity and length of time
that light strikes the water of a freshwater ecosystem. Species of plants rely on a critical
period of time where they receive light for photosynthesis.
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Season - The 4 seasons in an ecosystem are very different, and this is because less light
and heat is available from the sun in Winter and vice versa for Summer, therefore these
varying conditions will affect which organisms are suited to them.
Location - The extreme latitudes receive 6 months of sunlight and 6 months of darkness,
while the equator receives roughly 12 hours of sunlight and darkness each day. This sort of
variance greatly affects what type of organisms would occupy freshwater ecosystems due
to these differences.
Altitude - For every one thousand metres above sea level, average temperature drops by
one degree Celsius. Altitude will also affect the aspect of which sunlight hits the
freshwater ecosystem, therefore playing a part on which organisms will occupy it.
As you can see, many abiotic factors can play a part in determining the end product, which
organisms live and succeed in the freshwater ecosystem. The sun provides light for
photosynthesis, but also provides heat giving a suitable temperature for organisms to thrive
in. The temperature of a freshwater environment can directly affect the environment as a
whole and the organisms that occupy it.
Enzymes operate best at an optimum temperature, and any deviation from this temperature
'norm' will result in below optimum respiration in the organism. All aquatic life are
ectotherms, meaning their body temperature varies directly with its environments.
Temperature affects the density of substances, and changes in the density of water means
more or less resistance for animals who are travelling in the freshwater environment.
http://www.biology-online.org/6/4_abiotic_factors.htm
ABIOTIC FACTORS
The abiotic factors are those inert factors of the ecosystem; for example, light,
temperature, chemical products, water and atmosphere.
LIGHT
Light is an essential abiotic factor in the ecosystems because it constitutes the main
supply of energy for organisms. The plants with chlorophyll can change the light energy
into chemical energy thanks to the process known as photosynthesis. This chemical
energy is stored in complex organic substances (food). It is useless to say that without
light there would not be living beings on Earth.
Besides this significant function, the light regulates many biological rhythms of a large
amount of species.
Visible light is not the only form of energy emitted by our Sun. The Sun propels several
forms of energy, from radio waves to gamma energy. Ultraviolet light (UV) and infrared
radiation (heat) are found among these forms of solar radiation. Both UV light and infrared
radiation are abiotic factors of high significance for Ecosystems.
Insects use ultraviolet light to differentiate one flower from another. Humans cannot
perceive UV radiation. UV light works also limiting some biochemical reactions that could
be harmful for the living beings; besides, UN light annihilates pathogens and can cause
favorable mutations in all life forms. Recently, GB scientists discovered that the birds
orient themselves by means of the perception of small differences in the reflection of light
UV by the objects on land, for example edifice, trees, water surfaces, rocks, etc.
HEAT
Heat is useful for ectothermic animals, to be precise those that are not adapted to regulate
their corporal temperature (by example fishes, amphibians and reptiles). Plants make use
of a little amount of heat to perform the photosynthetic process. Plants are adapted to
survive between a minimum and a maximum limit of temperature. This is valid for all the
organisms, from archaea to Mammalia. Although some microorganisms unusually tolerate
extreme temperatures, they would perish if they would be retired from those rigorous
environments.
When the infrared radiation incoming from the Sun penetrates into Earth’s atmosphere, the
atmospheric water vapor absorbs it and delays the release of heat towards the space;
consequently, the atmosphere is kept warm (greenhouse effect).
The oceans play an important role in the stability of the terrestrial climate. The difference
of temperatures in different masses of oceanic water in combination with winds and
Earth’s rotation creates the oceanic currents. The transfer of heat emitted or absorbed by
oceanic water permits that some cold volumes of the atmosphere warm up and that
warmer volumes of the atmosphere are cooled.
ATMOSPHERE
The happening of life upon our planet would be barely possible without our existing
atmosphere. Many planets in our solar system have an atmosphere, but the structure of
the terrestrial atmosphere is the ideal for the origin and the perpetuation of the as we know
life. Its constitution does that terrestrial atmosphere be so special.
The terrestrial atmosphere is formed by four concentric superimposed layers, which are
extended up to 80 kilometers. Divergence in their temperatures differentiates these layers.
The layer that is extended over the terrestrial surface close to 10 kilometers is called
troposphere. In this layer the temperature diminishes in inverse proportion with the height,
that is to say, to greater height a smaller temperature. The minimum temperature at the
top of the troposphere is -50°C.
Troposphere contains three quarters of all the molecules of the atmosphere. This layer is
in continuous movement, and nearly all the meteorological phenomena take place in this
layer.
The next layer is the Stratosphere, which extends starting at 10 km up to 50 km in altitude.
The temperature increases proportionally to the height here; to greater height, greater the
temperature. At the top of the stratosphere, the temperature almost reaches 25 °C. the
cause of this ascent in the temperature is the ozone layer (ozonosphere).
Ozone absorbs the Ultraviolet radiation that breaks the molecules of Oxygen (O2),
generating freed atoms of Oxygen (O), which are connected again to build Ozone
molecules (O3). In this type of chemical reactions, the transformation of luminous energy
into chemical energy generates heat that provokes a greater molecular movement. This is
the reason for the ascent of the temperature in the stratosphere.
The ozonosphere has an unmatched consequence for the life, given that it stops the solar
emissions that are lethal for the totality of the organisms.
If we imagine the layer of ozone like a football, we would see the Ozone Layer Depletion
similar to a deep depression upon the skin of the ball, as if it was barely deflated.
WATER
Water (H2O) is an indispensable factor for the life. Living beings were originated in water,
and all living beings need water to subsist. Water is involved in diverse organic chemical
processes, for example water molecules are used during the photosynthesis, freeing
oxygen atoms of water.
Water works as a thermoregulator for climate and living systems: Thanks to water the
climate on Earth is maintained stable. The water functions also as thermoregulator in the
living systems, especially in endotherm animals.
Before an elevation of the temperature in the surrounding environment, the temperature of
a mass of water will rise with greater slowness than that of other materials. Equally, if the
surrounding temperature diminishes, the temperature of that mass of water will diminish
with more slowness than that of other materials. Thus, this quality of water permits that
aquatic organisms live relatively placidly in an environment with stable temperature.
Evaporation is the change of the physical state of a substance from a liquid physical state
to a gaseous physical state. We need 540 calories to evaporate a gram of water. At this
point water boils (point of boiling). This means that we have to rise the temperature at
100°C to do water boils. When evaporates from the surface of the skin, or from the surface
of leaves of a plant, water molecules drag large quantities of heat with it. This works in the
organisms like a cooling system.
Another advantage of the water is its melting point. With the intention that a liquid
substance change from a physical state liquid to a physical state solid, it should be
extracted heat from that substance. The temperature at which a substance change from a
physical liquid state to the physical solid state is called melting point. To change the water
physical state from liquid to solid we have to diminish the surrounding temperature at
0°C.To revert melting, this is to say to change one gram of ice to liquid water, it requires a
supply of 79.7 calories. When water melts, the same amount of heat is liberated to the
surrounding environment. This allows that in winter the environmental temperature does
not decrease to the point of annihilate all the life on the planet.
CHEMICAL ELEMENTS
Living beings are constituted by matter. From the 92 known natural elements, only 25
elements are found in the living matter. From these 25 elements, four elements, Carbon,
Oxygen, Hydrogen and Nitrogen, are present in the 97% of the molecules of life. The
remaining elements compose only the 3% of the living matter, being the most important
Phosphorus, Potassium, Calcium and Sulfur.
Molecules containing Carbon in their structures are called Organic compounds; for
example, the Carbon Dioxide, which is formed by an atom of Carbon and two atoms of
Oxygen (CO2). Compounds that have not Carbon in their structure are known as Inorganic
Compounds; for example, a molecule of water, which is formed by an atom of Oxygen and
two of Hydrogen (H2O).
BIOTIC FACTORS
Biotic factors are all the organisms that share an environment.
Biotic Components are all the living beings in an environment, from protists to
mammalians. Individuals should have specific behavioral and physiological characteristics
that permit their survival and reproduction in a defined environment. The condition of
sharing an environment generates a competence among the species, competence that is
given for food, space, etc.
We can say that the survival of an organism in a given environment is limited so by the
abiotic factors as by the biotic factors of that environment.
The biotic components of an ecosystem are found in the ecological organizational
categories, and they constitute the food chains in the ecosystems.